Blood vessel valves include flexible tissue leaflets that passively alternate between open and closed positions as the forces of a blood stream act upon them. As blood flows in a first direction, the leaflets are urged apart from each other, and allow the blood to pass. Between pulses, as the blood attempts to flow in a reverse direction, the blood acts upon upstream surfaces of the individual leaflets, causing the leaflets to move inwardly. As the leaflets move inwardly, the edges of the individual leaflets (two, in the case of bicuspid valves, and three in the case of tricuspid valves) abut against each other, effectively blocking the blood flow in the reverse direction.
If the individual leaflets suffer degradation in structural integrity, such as degeneration, a prolapse condition may result. FIGS. 1 through 3 demonstrate the mechanics of a regurgitant valve with leaflet prolapse. FIGS. 1a and 1b show a healthy tricuspid valve 1 in the open position. The direction of blood flow is indicated by arrow 2. The valve 1 includes three leaflets 3 growing into the lumen of a blood vessel 4. It can be seen that when the blood is flowing in the direction shown by arrow 2 of FIG. 1a, the flexible valve leaflets 3 naturally fold themselves against the interior walls of the blood vessel 4, thereby minimizing their impact on blood flow in that direction.
As depicted in FIG. 2a, when blood attempts to flow in the reverse direction, between cardiac pulses, these valve leaflets 3 move inward, toward each other. As best shown in FIG. 2b, when the leaflets 3 abut, they form a seal 5, effectively preventing fluid flow in the direction of arrows 2 from FIG. 2a. The seal 5 can only be formed if all three valve leaflets 3 are structurally sound.
When a valve, such as valve 1 of FIG. 3, has a prolapsed leaflet 3a, the seal 5 cannot be effectively formed. Leaflet 3a lacks the structural integrity of the healthy leaflets 3. When the flow is reversed, as indicated by arrow 2, the healthy leaflets 3 balloon inwardly. However, the prolapsed leaflet 3a falls away from the seal 5, leaving a significant gap 6 in the seal 5. Blood passes through the gap 6, resulting in a loss of systolic pressure, as well as a reduction in the pumping efficacy of the heart.
Current methods of repairing prolapsed valves involve replacing the valve entirely with a prosthetic valve. The structurally sound leaflets are not preserved. It would be advantageous to provide a method of repairing a prolapsed valve, leaving as much of the native valve as possible intact, thereby minimizing the risk of rejection, and preserving the healthy leaflets. Percutaneous treatment would obviate the risks associated with open heart surgery.